1. Abstract Motivation Background Final Design Future Work References Acknowledgements Mechanical Design Electronic Design Leon Corbeille Neal Haas Joe Helfenberger Peter Kleinschmidt Lein Ma Client: Carla Alvarado, PhD 1 Advisor: John Webster, PhD 2 1 Center for Quality and Productivity Improvement – University of Wisconsin – Madison 2 Department of Biomedical Engineering – University of Wisconsin Madison Device Operation Sequence: 1.Keyboard input by from any keystroke 2.Square wave signal routed to microcontroller 3.Microcontroller simultaneously switches power source leads from +/+ (off) to +/- (forward) through single throw double pole relays to isolate power 4.Forward stroke of actuator occurs 5.Microcontroller switches power source leads to -/+ (reverse) 6.Spray stops and actuator retracts to stop spray and refill pump 7.Microcontroller switches power source leads to +/+ in preparation for next run 1 2 3, 5, 7 4, 6 Infection is the most common source of medical error in healthcare in America and poor sanitation and hand hygiene are the leading sources of bacterial colonization and communication. An interventional hand sanitization device to improve workspace cleanliness could therefore improve healthcare proficiency and dramatically reduce healthcare costs. A device has been constructed to automatically dispense a disinfectant as a fine mist over a keyboard after automatically being initiated by computer use. The sanitizer serves to both clean the keyboard and the users hands with a short, controlled spray. The device functions by atomizing a liquid disinfectant through a high pressure pumping mechanism. The trigger is initiated by a microcontroller linked to a linear actuator and the initiation signal is captured by the microcontroller from a signal taken from the keyboard cable,. Any keystroke activates the spray. Future work will include refining of the spray and streamlining the device to better integrate into the hospital environment. 1. 12 V Linear Actuator Provides pressure to pump disinfectant solution through syringe. 2. Black Bulk PVC (2"x2"x1.5') Used to securely hold syringe and plunger, connects entering and exiting hose connectors. 3. Clear 1/4“TubingUsed to connect nozzle to hose connecters located in the PVC. 4. Wooden FrameWhere the nozzle is attached to. Surrounds keyboard. 5. Copper-Nickel No‐Drip Misting Nozzle 1/8 in Pipe size, Produces a fine mist that sprays keyboard 6. Barbed Brass Hose Connector Connects the clear tubing to the PVC and the tubing to the nozzle 7. 0.85 in. Medical Syringe and Plunger Used to hold disinfectant in PVC. Plunger forces liquid through tubing 8. Ball-Check ValveProvides non-reversible flow from the nozzle connection to the tubing connection The nozzle needs high pressure from a powerful actuator to spray. The nozzle and the actuator should be scaled down to a more efficient size, making it more cost- and space-effective. The nozzle could be integrated directly into the keyboard during production, eliminating extra framework and compacting the design. However, a more sophisticated version of the nozzle stand would work universally with existing keyboards, eliminating the need to purchase new hardware. The Parallax microcontroller is both expensive and bulky. Changing to a different type of microcontroller would make the devise much cheaper and smaller. The flexibility of a stamp allows the user to customize the configuration so a standard integrated circuit would hinder this key feature. The disinfecting solution must kill 99.99% of bacteria without harming the user and without clogging the nozzle. Finding a formula which maximizes comfort and integrates seamlessly with this system requires extensive chemical knowledge. Further testing with commercial products or custom solutions still needs to be done. Previous Work Limitations Testing — Durability: Keyboard still functional after 48 hours of emersion in 70% alcohol solution — Effectiveness: Significant reduction in bacteria presence when disinfectant is used — Usability: 78% of potential users neutral or comfortable with disinfectant solution Prototype — LabVIEW dependent program - Predefined keystroke activated - Drives actuator and pump system — Fogging nozzle provides a hollow cone spray — Syringe used as pumping system Computer-dependent program - Requires expensive program - Computer runs virtual circuit – difficult to implement - No guaranteed keystroke exists in the industry Fixed nozzle location on the work table Loosely supported device - Nails and zip ties held down components - Syringe not designed for high pressure Professor Willis Tompkins – Department of Biomedical Engineering Dr. Tosha Wetterneck – Center for Quality and Productivity Improvement Amit Nimunkar – Department of Biomedical Engineering Fall 2007 Hand Washing BME Design Team Martone WJ, Jarvis WR, Culver DH, Haley RW. 1992. Incidence and nature of endemic and epidemic nosocomial infections. In: Bennett JV, Brachman PS, eds. Hospital infections.577(96). Swoboda S, Lane S, Strauss K, Lipsett P. 2002. The Evidence: Hand Hygiene Impacts Nosocomial Infection Rates.Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 42: 27-30 Bischoff, W.E. et al. “Handwashing compliance by health care workers: The impact of introducing an accessible, alcohol- based hand antiseptic.” Arch Intern Med. 2000 April; 10 (160): 1017-1021. Klevens, R. Monina et al. “Estimated Health care-Associated Infections and Deaths in US Hospitals, 2002.” Public Health Reports. 2007 March; 122: 60-66. Hospital related infections are unacceptably high: 1.7 million annual hospital-related infections 99,000 associated annual deaths (Klevins et al 2002) Total economic burden estimated at $4.5 billion (Martone et al 1992). Hand washing has been shown by many studies to be directly related to hospital related infections. (Swoboda et al 2002). Compliance to health care hand washing standards remains unacceptably low, with current studies revealing compliance rates at 30-60% (Bischoff et al 2000). Throughout recent history, a lack of integration into the work flow has been shown to be the biggest factor affecting compliance (Swoboda et al 2002). To fix this, a system change is needed. As computer kiosks become more widely used in health- care settings, it becomes difficult to create a clean environment without interrupting workflow. Goal: to create a passive device that sanitizes a health- care worker’s hands and the keyboard they are using, creating a cleaner environment and improving compliance with hygienic procedures.